Why Couldn't There Be Several Gods?

An ancient intuition: if the universe is so vast, why should its source be unique?

The objection is at least three thousand years old. Most peoples of antiquity honored a plurality of divinities: Mesopotamians, Egyptians, Greeks, Romans, Germans, Celts, Mayas, Aztecs, Chinese, Indians. Only Israel maintained the confession of one God amid this overwhelmingly polytheistic environment^[4]. According to the traditional biblical chronology, this confession goes back to Abraham (around the 19th century B.C.); historical-critical exegesis, of which M. S. Smith is a representative, places its explicit formulation at a much later date instead (see objection 4 below). Strict monotheism is therefore historically the exception, not the rule. The spontaneous intuition of religious humanity would lean rather toward multiplicity.

To this historical pressure is added today a cultural pressure: globalization brings the great religions into contact, and the vague feeling that "all religions are equal" leads people to imagine behind each tradition an equivalent divine figure — so many faces of one same mystery, if not so many competing gods. Why claim that Catholic metaphysics is right against the billions of polytheist, Hindu, animist, or neo-pagan believers who still populate the planet?

The contemporary objection: "you have demonstrated existence, not uniqueness"

In its philosophical form, the contemporary objection is often this: the classic arguments for God's existence (the cosmological argument, contingency, the way of finality, fine-tuning) conclude only to "at least one first cause." They do not rule out several of them, or their cooperating like a divine consortium. To move from "at least one" to "exactly one" requires an additional argument — and that is precisely what the Thomist ways to divine uniqueness supply. The demonstration of existence is not the final step of philosophical theism: the step of uniqueness is.

Everything depends, in reality, on the meaning given to the word "God." Depending on the meaning adopted, plurality is trivial or contradictory. Three different meanings occur in the debate, and they must be rigorously distinguished before any other argument.

Mythological "gods": finite powers within the world

When a modern reader hears the question "why not several gods?", he spontaneously pictures Homer's divinities, the Egyptian pantheon, or the superheroes of the Marvel Cinematic Universe: powerful but finite beings, above us, endowed with particular powers, competing with one another. On this picture, the objection seems obvious: why one, rather than ten?

But the "gods" of classical polytheism are not God in the sense of philosophical theism. Zeus is born, quarrels, errs, desires; he governs the sky but not the sea. Poseidon is not Athena; Mars is not Venus. Each has a name, a territory, competences, and limits — they are beings within the world, more powerful than we are, but inscribed in a cosmic order that surpasses them. Hesiod recounts their birth in the Theogony^[5]: they have a genealogy, hence an origin. But what has an origin is not the first cause. Homer, more radical still, shows Aphrodite wounded in the hand by Diomedes' spear (Iliad V, 335-340)^[6]: a god who bleeds is not a necessary God.

The God of metaphysics: ultimate principle of being

The philosophical question is therefore not "how many very powerful celestial characters exist?" It is: what is the ultimate principle on which everything depends? At this level, plurality ceases to be plausible. Aristotle, who was nothing of a Jew or a Christian, concludes already in Metaphysics XII, 8 that the First Mover is numerically one, because it is pure act without matter, and matter alone individuates numerically beings of the same nature^[7].

In simple words: "pure act without matter" means fully real, without any bit of matter bounding it — and "matter alone individuates" means that two copies of one same thing differ only by their material support: two gold rings differ by their gold, not by their ring-form. Without matter, there can therefore be no "second copy" of God.

"It is clear, moreover, that there is only one heaven. […] As for the first essence, it has no matter, for it is entelechy. Therefore the first mover, the immobile mover, is one, both formally and numerically; and what is in eternal and continuous motion is unique; therefore there is only one heaven." — Aristotle, Metaphysics, book XII (Λ), 8, 1074a 31-1074b 14^[8]

This Aristotelian insight would be taken up and deepened by the monotheist philosophers of the three Abrahamic traditions: Avicenna (Ibn Sīnā, 980-1037) in the Metaphysics of the Shifā'^[9], Maimonides (1138-1204) in the Guide for the Perplexed^[10], and Thomas Aquinas (1224-1274) in the Summa Theologiae. For all of them, the God of metaphysics is not a thing in the world: he is subsistent Being itself, ipsum esse subsistens^[11].

The God of biblical Revelation: one Lord, creator and Father

The God of Israel and of the Church is not an abstract deduction, but a personal God who speaks, who acts in history, who reveals himself. The central confession is the Shema Israel:

"Hear, O Israel: the Lord our God, the Lord is ONE. You shall love the Lord your God with all your heart, with all your soul, and with all your strength." — Deuteronomy 6:4-5^[12]

This verse, prayed twice daily by the pious Jew, is quoted verbatim by Jesus in Mk 12:29^[13]: "The first of all the commandments is: Hear, O Israel, the Lord our God is the one Lord." The Catechism comments:

"The confession of God's oneness, which has its root in the divine Revelation of the Old Covenant, is inseparable from the confession of God's existence and is equally fundamental." — Catechism of the Catholic Church, § 200^[14]

Catholic tradition therefore teaches that the three meanings converge: the personal, creator God of Scripture is the same as the metaphysical principle reached by natural reason. That is why the council of Vatican I (1870) defined that God can be known "with certainty by the natural light of human reason, from created things" (DS 3004)^[15], and that this rational knowledge is coherent with revealed knowledge. The three meanings are not competitors: together they illuminate a single reality.

Summary table of the meanings of the word "God"

Before engaging the proofs, what belongs to metaphysics and what does not must be clearly distinguished. The following table gathers the possible cases and specifies which ones are concerned by the Thomist ways to divine uniqueness.

The first column designates what the Bible sometimes calls "the gods of the nations" — that is, idols with no divine reality of their own, or subordinate spirits wrongly identified. Psalm 96:5 is categorical: "For all the gods of the nations are idols ('elilim, vanities)." ^[16] And Saint Paul, before the many statues of Athens, will take up the argument again by pointing to "the unknown God" behind the popular divinities (Acts 17:23)^[17]. It is the fifth and sixth rows — Brahman and the biblical God — that the Thomist ways directly concern.

Saint Thomas devotes an entire article of the Summa Theologiae to the question "Is God one?" (I, q. 11, a. 3). He gives there three ways that remain today the heart of Catholic argumentation on uniqueness. They all start from the same principle: God is not one being among others, but Being itself. If this definition is granted, plurality is impossible.

To set the stage: what Thomas has already established

Before his three ways, Thomas established in the preceding questions what he calls the negative attributes of God — not because they deny something, but because they set aside the imperfections of the created world. God is simple (q. 3, without composition of parts), perfect (q. 4, without lack), infinite (q. 7, without limit). These three traits form the ground of the proof of uniqueness: if God is without parts, without lack, and without limit, then multiplying him makes no sense.

First way: divine simplicity

The argument rests on what Thomas demonstrated earlier (ST I, q. 3): in God, essence and existence are identical. In every creature, essence (what it is) is distinct from existence (that it is); humanity is shared among billions of individuals because it is received in each of them. But God does not have a received being — he is his being.

"It is manifest that what makes a singular being this singular being cannot be communicated to several. That by which Socrates is a man can be communicated to many; but that by which he is this singular Socrates can be communicated to one alone. If therefore Socrates were a man by the very fact by which he is this Socrates, there could not be several men, just as there cannot be several Socrates. Now, this is what takes place in God: for God is himself his own nature. Therefore, by the same reason, God is God, and God is this God. It is therefore impossible that there be several gods." — Thomas Aquinas, Summa Theologiae, I, q. 11, a. 3^[18]

In plain terms: the analogy of whiteness itself

The idea is simple, once grasped. You can have several men because humanity is a nature received in distinct individuals: Peter, Paul, Joan are three copies of human nature, like three flames of the same fire. But in God there is no distinction between the divine nature and the divine individual: God is his nature. The divine nature is therefore not a mold received in several copies; it is itself this unique copy.

As an image, take whiteness itself, considered not as the quality of an object, but as pure whiteness, independently of any support. How many are there? Only one. You can have a thousand white objects, but only one whiteness-itself making them white. Multiplying whiteness-itself would be absurd — each would need something the other lacks, and then neither would be whiteness-itself anymore. The same reasoning holds, more strongly still, for Being itself which is God.

Second way: infinity of perfection

The second argument is even more direct, and it is probably the most powerful for a modern mind. God, as first cause, contains in himself all the perfection of being: there is not, outside him, a goodness, an intelligence, or a power that he lacks. If there were two gods, each absolutely infinite, they would have to differ — otherwise they would not be two, but the same.

"God comprehends in himself all the perfection of being. If therefore there were several gods, they would have to differ from one another. Something would therefore belong to one which would not belong to the other. And if it were a privation, the one would not be absolutely perfect; if it were a perfection, the other would be deprived of it. It is therefore impossible that there be several gods." — Thomas Aquinas, Summa Theologiae, I, q. 11, a. 3^[19]

Why the argument is relentless

The argument works like a pincer. Either A possesses something B lacks: then B is not God, for it lacks a perfection; or B possesses something A lacks: and then it is A who is not God. Or they differ in nothing — and then they are not two. Multiplicity presupposes distinction; distinction presupposes a limit or determination; but God, as infinite, has no inner limit.

This is Avicenna's reasoning on necessary existence that Thomas takes up, six centuries later, in the Summa contra Gentiles: "If there are two beings, each existing necessarily, they must agree in respect of necessary existence; they must therefore be distinguished by some addition. But what requires an addition is not absolutely necessary." ^[20] Maimonides, later, will say simply:

"There can be no faith in the unity of God except by admitting that he is a simple substance, without any composition or plurality of elements; one, from whatever side one considers him and by whatever test one examines him; not divisible into two parts in any manner and by any cause, nor capable of any form of plurality, objectively or subjectively." — Maimonides, Guide for the Perplexed, II, ch. 1^[21]

This convergence is remarkable: an 11th-century Muslim, a 12th-century Jew, and a 13th-century Catholic independently reach the same conclusion, because they reason on the same metaphysics of being. Divine uniqueness is not a confessional dogma: it is a demand of thought itself when it pushes analysis to the end.

Third way: the unity of the order of the world

Thomas's third way starts no longer from the divine essence but from the observation of the cosmos. The universe manifests a coherent order: physical laws are the same here and in the Andromeda galaxy; mathematics applies everywhere; beings are linked in oriented hierarchies. But "plurality is better reduced to unity by one than by several," and a common order points back to a common source of unification.

"All things that exist are seen in order among themselves, insofar as some serve others. But diverse things would not agree in one same order, except through someone who orders them. For plurality is better reduced to unity by one than by several. Therefore there is a single first one who brings all things into order, who is God." — Thomas Aquinas, Summa Theologiae, I, q. 11, a. 3^[22]

An intuition modern science makes stronger

This argument anticipates what contemporary defenders of the fine-tuning of the universe emphasize: if several first causes independently governed distinct domains, one could not understand why the physical constants of one domain agree so exactly with those of another. The agreement of gravity, electromagnetism, the weak and strong nuclear forces, thermodynamic constants, etc., in a coherent and fruitful cosmic order, suggests a single source of unification.

The current cosmological model proposes a profoundly one universe: a single age, a common origin (the Big Bang), a single cosmic microwave background, the same mathematizable laws from one end of the observable cosmos to the other. But this picture remains a scientific reconstruction: it assumes the physical laws measured today can be extrapolated back to the first instants of the universe. If this model is correct, then the observed physical plurality would unfold within a deeper unity — which would remain coherent with what the third way leads one to expect if the first cause is itself one.

Complementary argument: the first cause cannot be plural

In the Summa contra Gentiles (book I, chapter 42), Thomas aligns ten convergent arguments for God's uniqueness — notably the argument of the sovereign good ("There cannot be two sovereign goods") and the argument of necessary existence:

"If there are two beings existing necessarily, they must agree in respect of necessary existence. They must therefore be distinguished by some addition made to one or to both; and thus either one or both must be composed. But no composite being exists necessarily of itself. Therefore there cannot be several necessary beings, nor several gods." — Thomas Aquinas, Summa contra Gentiles, I, ch. 42^[23]

The argument is precious because it operates even if one refuses the Thomist premises on infinity or simplicity. As soon as one grants that there exists at least one necessary being — a being that cannot not exist, at the root of all the contingent — then there can be only one. Two necessary beings would have to be distinguished by something; this something would be an addition to their necessity; therefore neither would be absolutely necessary of itself alone. Necessary existence admits no plural.

Contemporary restatement: Edward Feser and pure actuality

The Thomist case has been restated for the contemporary philosophical reader by Edward Feser in Five Proofs of the Existence of God (Ignatius Press, 2017), where chapter 6 systematically examines the divine attributes. Feser's central thesis: a being of absolutely pure act (without any potentiality) can admit no inner or outer differentiation; it is therefore unique^[24]. A possible cosmological multiverse — several physical universes generated by one same mechanism — in no way affects this conclusion: multiplicity remains in the order of the contingent, and itself calls for a single first cause.

Feser also stresses that the uniqueness arguments are independent of revelation: they hold for the Jewish, Muslim, or Christian theist, and even for a philosopher with no particular religious tradition. When Aristotle, Avicenna, and Thomas converge, it is because the metaphysics of being leads them there, not because they share a confessional doctrine.

The Shema Israel, heart of monotheist faith

The Hebrew Bible does not demonstrate God's uniqueness as a theorem: it proclaims it as a commandment and confesses it as Israel's central evidence. "Hear, O Israel, the Lord our God is ONE" (Dt 6:4) — a verse prayed twice daily, placed in the mezuzah of doorways and written in the tefillin worn on forehead and arm.

The context is not neutral: Israel lived amid the pantheons of neighboring nations. In Babylon, where it would be deported, Marduk, Nabû, Ishtar, Shamash were worshipped. In Egypt, Ra, Isis, Osiris. In Canaan, Baal and Astarte. Throughout Scripture, the prophets wage a relentless polemic against idols. Isaiah makes God himself speak:

"I am the Lord, and there is no other, besides me there is no God. […] Turn to me and be saved, all the ends of the earth, for I am God, and there is no other." — Isaiah 45:5, 22^[25]

And further on, in a sarcastic tone, Isaiah mocks the craftsman who makes an idol out of one piece of wood and burns the other half he used for his fire (Is 44:12-20)^[26]. The strength of biblical monotheism is not only metaphysical: it is also moral and historical — a God who reveals himself in a concrete history, who frees from Egypt, who speaks through the prophets.

Jesus confirms and unfolds Jewish monotheism

Christianity does not overturn Jewish monotheism: it confirms and unfolds it. When a scribe asks Jesus which is the first commandment, his answer is unambiguous:

"The first is: 'Hear, O Israel, the Lord our God is the one Lord. You shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength.'" — Gospel according to Saint Mark 12:29-30^[27]

Paul, the apostle to the nations, preaches to pagan Athenians one God behind the altar "to the unknown God" (Acts 17:23)^[28]. To the Corinthians, he writes clearly:

"As to eating food sacrificed to idols, we know that there is no idol in the world and that there is no God but the One. For although there may be, whether in heaven or on earth, what are called gods — and indeed there are many gods and many lords — yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist." — 1 Corinthians 8:4-6^[29]

The text is decisive: Paul acknowledges that there exist "what are called gods" — that is, beings peoples honor as such — but for Christians, there is really only one God. Thomas will comment relying exactly on this verse: these other "gods" are named by participation, not by nature^[30]. They are not God, but creatures, deceiving demons, or mere idols without reality.

A reading that does not oppose reason and faith

One essential trait of Catholic tradition should be noted here: the Bible and metaphysics are not competitors; they converge. The Shema proclaims what Thomas demonstrates. The greatness of Catholicism lies precisely in holding both together — Revelation as the gracious gift of a God who speaks, and reason as man's natural capacity to recognize that this God can only be one. Vatican I would dogmatically affirm this compatibility in chapter 4 of Dei Filius: "Although faith is above reason, there can never be any real dissension between faith and reason" ^[31].

The Symbol of Nicaea-Constantinople (325-381)

Even before the medieval and modern councils, the Church confesses divine uniqueness already at Nicaea (325) and Constantinople I (381) in the Creed recited at every Sunday Mass:

"Credo in unum Deum, Patrem omnipotentem, factorem caeli et terrae. […] Et in unum Dominum Iesum Christum, Filium Dei unigenitum… Credo in Spiritum Sanctum, Dominum et vivificantem." — Symbol of Nicaea-Constantinople, 325/381^[32]

Three times the word unum — one God the Father, one Lord Jesus Christ, one Holy Spirit — to confess, paradoxically, one God in three Persons. The council of Nicaea explicitly fixes the homoousios (consubstantiality) of the Son with the Father^[33], ruling out Arianism, which would have led to a disguised di-theism. It is precisely because Christianity holds absolutely to divine uniqueness that it had to develop the Trinitarian dogma in its definitive rigor.

Lateran IV (1215) — Firmiter credimus

The Fourth Lateran Council (1215), convened under Pope Innocent III, opens its first constitution De fide catholica with a profession of faith that has become the classic magisterial formulation of Trinitarian uniqueness:

"We firmly believe and simply confess that there is one true God alone, eternal, immense and unchangeable, incomprehensible, almighty and ineffable, Father and Son and Holy Spirit: three persons, but one essence, one substance or nature entirely simple." — Fourth Lateran Council, constitution Firmiter credimus, 1215, DS 800^[34]

This text, quoted verbatim by the Catechism at paragraph 202^[35], indissolubly knots together two affirmations: divine uniqueness and absolute simplicity. The Trinity, far from weakening uniqueness, is its revealed deepening.

Vatican I (1870) — Dei Filius, God distinct from the world

More than six centuries after Lateran IV, the First Vatican Council (1869-1870), faced with the rise of German pantheism, materialism, and agnosticism, gives divine uniqueness a very precise formulation again in the dogmatic constitution Dei Filius:

"The holy Catholic, apostolic, Roman Church believes and confesses that there is one true and living God, creator and Lord of heaven and earth, almighty, eternal, immense, incomprehensible, infinite in intellect, in will, and in all perfection; who, being one single spiritual substance, singular, absolutely simple and immutable, must be proclaimed really and essentially distinct from the world, perfectly happy in himself and of himself, and ineffably exalted above all that is or can be conceived besides him." — First Vatican Council, constitution Dei Filius, ch. 1, 24 April 1870, DS 3001^[36]

The canons annexed to this constitution pronounce anathema against whoever "denies that there is one true God" (canon 1), against whoever "affirms that there is nothing but matter" (materialism, canon 2), or against whoever "says that the substance or essence of God and of all things is one and the same" (pantheism, canon 3)^[37]. Metaphysical polytheism, materialism, and pantheism thus fall under the same dogmatic condemnation.

The Catechism: "one God in nature, substance, and essence"

The Catechism of the Catholic Church synthesizes this tradition in several dense paragraphs (§§ 199-202) opening with the first word of the Creed, credo in unum Deum. It quotes the Roman Catechism (1566):

"The Christian faith confesses that there is one God, in nature, in substance, and in essence." — Roman Catechism, I, 2, 8, quoted by CCC § 200^[38]

This threefold precision — nature, substance, essence — is directed against every possible form of disguised polytheism: not only one God in number, but one God in his very being, his ontological reality, his metaphysical essence.

The classic case for divine uniqueness must now face a number of objections — from interreligious dialogue, historical-critical exegesis, contemporary cosmology, or the philosophy of religion. None of them, examined in its strongest version, overturns the metaphysical argument.

Objection 1 — "Hinduism worships millions of gods; the legitimacy of polytheism must at least be recognized"

Strong formulation. Hinduism honors more than 330 million devas: Brahma, Vishnu, Shiva, Krishna, Rama, Ganesha, Lakshmi… This is not only a popular imagery; it is a spiritual tradition more than three thousand years old, recognized by Vatican II (Nostra Aetate §2) as containing "true and holy elements" ^[39]. Why disqualify Hindu plurality out of hand? Especially since in Shankara's Advaita Vedanta (traditionally dated 788-820; disputed chronology, recent research placing his life rather in the first half of the 8th century), all gods are manifestations of a single Absolute, Brahman, and learned Hinduism is in fact monist, not polytheist.

Catholic answer. The objection actually mixes two very different theses.

On the one hand, Hindu popular polytheism (concrete veneration of Krishna or Ganesha) falls under the same case as Greek polytheism: these are finite powers, to be classed as idols, subordinate spirits, or mythological figures according to the case — not as competing first causes. The Bhagavad-Gita itself has Krishna say: "O son of Kunti, even those devotees who faithfully worship other gods worship Me in reality — but in an incorrect manner" (Bhagavad-Gita 9:23)^[40]. The text thus suggests a convergence toward a supreme God behind the manifestations.

On the other hand, Shankara's Advaita Vedanta is not polytheist: it is monist. Its classic formula "Brahma satyam, jagan mithyā" ("Brahman is real, the world illusory")^[41] affirms a single Absolute. But this monism is not monotheism in the Catholic sense:

1. The nirguna Brahman is impersonal: it has neither intelligence, nor will, nor love as distinct attributes. The Christian God is personal: he knows, he wills, he loves.
2. Brahman is not creator ex nihilo: the world illusorily emanates from it (māyā). The God of the Bible and of Vatican I is "creator and Lord of heaven and earth," "really and essentially distinct from the world" ^[42].
3. In Advaita, the individual soul (ātman) is identical with Brahman: "Aham Brahmāsmi," "I am Brahman." Christianity distinguishes creator and creature and formally condemns this identification (CCC § 285 against pantheism).

The Church therefore recognizes with Vatican II that Hinduism contains "rays of that Truth which enlightens all men" ^[43], and that the mystical quest for Brahman can be a serious spiritual journey. But it maintains that there is only one personal God, creator and Father, and that no other tradition reaches God in the same way as Christian Revelation^[44]. For detailed treatment, see Hinduism.

Objection 2 — "Mormonism explicitly teaches several gods"

Strong formulation. Unlike other religions, Mormonism (The Church of Jesus Christ of Latter-day Saints) openly claims a divine plurality. Joseph Smith (1805-1844) taught in his famous King Follett Discourse of 7 April 1844:

"God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens!" — Joseph Smith, King Follett Discourse, 7 April 1844, Nauvoo (Illinois)^[45]

Lorenzo Snow, fifth LDS president, drew from it the couplet that became emblematic: "As man now is, God once was; as God now is, man may become" ^[46]. The Pearl of Great Price (Book of Abraham 4-5) systematically uses "the Gods" in the plural for creation, and the revelation Doctrine and Covenants 132:20 promises the faithful sealed in the temple that they "shall become gods."

Catholic answer. Mormonism is a form of exaltationist polytheism — precisely what the Magisterium denounces.

On 5 June 2001, the Congregation for the Doctrine of the Faith, under the signature of Cardinal Joseph Ratzinger, published an official Response declaring invalid baptism conferred in The Church of Jesus Christ of Latter-day Saints^[47]. The justification, set out by Archbishop Luis Ladaria in L'Osservatore Romano (1 August 2001), lies precisely in this: the Mormon Father, Son, and Holy Spirit are not the Christian Father, Son, and Holy Spirit. In LDS theology, the Father is an exalted man with a beginning, a physical body, who rose to divinity; the Son is a being begotten in time; the Holy Spirit is a distinct personal being without a body. This is therefore a graduated plurality of divinities, not the one God of the Nicene Symbol.

On the metaphysical plane, the Mormon objection falls under the Thomist argument of the second way: if God A became God by rising from a human condition, then he is not the necessary being; he had a beginning, hence an anterior cause, hence he is only one finite god among others. The Mormon "God" is not the God of Catholic metaphysics: he is an exalted creature. LDS doctrine, consistent with itself, moreover explicitly admits that the faithful too can become gods (D&C 132:20), which amounts to saying there exists an indefinite, and growing, number of divine beings^[48]. For detailed treatment, see The Mormons.

Objection 3 — "Manichaean and Zoroastrian dualism better explains evil"

Strong formulation. Two eternal and co-original principles explain the world better than one God: Good (Light, Ahura Mazda in Zarathustra; the Father of Greatness in Mani) and Evil (Darkness, Angra Mainyu; the Prince of Darkness) have clashed forever. This doctrine resolves the problem of evil at a stroke: God is not responsible for evil, because evil has its own source. Mani (216-276), a Babylonian prophet, synthesized Christianity, Zoroastrianism, and Buddhism into a powerful system that seduced the Roman Empire — and even a young man named Augustine of Hippo, a Manichaean for nine years before his conversion.

Catholic answer. It is precisely Augustine, become Catholic, who struck the decisive blow against dualism — to the point that all Western theology of evil bears his signature. His thesis, now classic, is that evil is not a positive substance, but a privation of being (privatio boni):

"The supreme good, above which there is nothing, is God, and thereby he is immutable good. […] Every nature that can be corrupted is itself a good; for corruption can harm it only by removing or diminishing what is good." — Saint Augustine, De natura boni, ch. 1 and 6 (399)^[49]

The decisive argument is simple. To exist, evil must lean on being (= on good) which it degrades: a pure, absolute evil, without any underlying good reality, would destroy itself. Blindness does not exist without an eye; sickness does not exist without a body; lying does not exist without an intelligence capable of truth. All are lacks of, not things in themselves. An "evil principle" equal to the good principle is therefore metaphysically impossible: it would have nothing on which to exercise its malice, being already the destruction of all being.

Thomas will take up and systematize the argument: "Evil is not something, but the privation of something" (ST I, q. 49, a. 1)^[50]. And he devotes the following article (I, q. 49, a. 3) precisely to the question "Is there a supreme evil that is the cause of all evil?" — answer: no, because evil is not a nature, so there is no positive supreme evil^[51]. Manichaeism actually feeds on bad metaphysical grammar: it treats evil as a thing, whereas it is the absence of a thing that ought to be there. The Catechism moreover explicitly lists Manichaeism among the erroneous answers to the question of origins (CCC § 285)^[52].

The dualist objection does not solve its own problem either: if Good and Evil clash within one same cosmic framework, this framework itself is more fundamental than they are. A common order is needed to let their energies meet, laws making their conflict possible, a shared space-time. The cause of this common order is neither of the two principles: it is the true one God. Dualism thus reduces to an imperfectly thought-out monotheism. Augustine himself, in his Confessions, recounts how his slow exit from Manichaeism (373-382) led him to understand that evil is not a substance facing God, but the free turning-away of a created will that is good^[53].

Objection 4 — "Ancient Israel was henotheist, not monotheist"

Strong formulation. Historical-critical exegesis has maintained for a century that pre-exilic Israel was not monotheist but henotheist or monolatrous: one God for Israel (YHWH), but other gods existing for other nations. The traditional position, recalled by the Pontifical Biblical Commission (response of 28 June 1908), holds that the book of Isaiah as a whole is the work of the prophet Isaiah (8th century B.C.), the oracles on the Exile being a genuine prophecy and not a later redaction. The most widespread hypothesis in historical-critical exegesis proposes on the contrary that strict monotheism appears only with chapters 40-55 (what it calls "Deutero-Isaiah" or "Second Isaiah"), which it dates to around 540 B.C., under the shock of the Exile. This bipartition remains a hypothesis: it assumes that a precise prophecy of the future would be impossible (an anti-prophetic presupposition), and it dates the text by the historical context it itself lends to it, which makes the dating circular. Mark S. Smith, in The Origins of Biblical Monotheism (Oxford University Press, 2001), defends the thesis that "YHWH was originally one of the seventy children of El, each being the tutelary divinity of one of the seventy nations" ^[54].

Several biblical texts are enlisted in support:

• Psalm 82:1: "God stands in the assembly of the gods; in the midst of the gods he renders judgment."
• Exodus 15:11: "Who is like you among the gods, O YHWH?"
• Deuteronomy 32:8-9: according to the Septuagint and a Qumran manuscript (4QDeutʲ), "he fixed the boundaries of the peoples according to the number of the sons of God" — a variant older than "according to the number of the sons of Israel" in the Masoretic text.

Catholic answer. The objection mixes historical exegesis, theology of Revelation, and metaphysics. It must be answered step by step.

First, Catholicism admits a progressive pedagogy of Revelation. The Catechism says explicitly: "This revelation of God as the One […] is rooted in the divine Revelation of the Covenant God made with Israel" (CCC § 200)^[55]. No one maintains that the nomadic Hebrews of the 13th century before Jesus Christ already possessed Aristotle's or Thomas's conceptual distinctions. The intellectual content of monotheist faith unfolded historically, as Joseph Ratzinger explained in Einführung in das Christentum (1968): it is a revelation embodied in a history, not a ready-made doctrinal system^[56].

Next, the texts cited do not prove genuine Israelite polytheism. Three remarks.

The word 'elohim is a plural of intensity

In Hebrew, 'elohim is a grammatical plural that can designate God (singular in meaning despite the plural form), angels, human judges, or the divinities of the nations — without committing to a metaphysics. When Ex 15:11 says "who is like you among the gods," the context is polemical: YHWH humiliates the gods of Egypt through the plagues — that is, he manifests their nothingness, not that he recognizes them as competing dignities. The following verse moreover proclaims "The Lord reigns forever and ever" (Ex 15:18).

Psalm 82 stages a judgment, not a pantheon

This psalm stages God's judgment against these "gods" who judge unjustly, and concludes: "Yet like men you shall die." Jesus himself quotes this passage in Jn 10:34-35^[57]; in a widely received reading, he applies it to the human recipients of the Word (judges or hearers of Israel), not to a pantheon. The word 'elohim there designates either human judges, or fallen angels in certain patristic readings — not divine rivals.

Deuteronomy 32:8 designates the angels of the nations

In the Septuagint / Qumran version, Dt 32:8 most probably designates the angels of the nations, created and subordinate beings. Catholic tradition admits the existence of guardian angels of peoples (cf. Daniel 10:13, 20 on "the prince of Persia" and "the prince of Greece" ^[58]), but these angels are not God. The following verse Dt 32:9 maintains without equivocation: "the Lord's portion is his people, Jacob his allotted heritage" — YHWH is the one God who apportions the nations.

The anti-idolatrous polemic rules out any serious henotheism

Finally, the prophets' anti-idolatrous polemic is so harsh that it rules out any serious henotheist reading. Isaiah mocks the craftsman who makes his god out of a piece of wood (Is 44)^[59]; Psalm 96:5 is categorical: "For all the gods of the nations are idols" ('elilim, vanities, nothingness)^[60]. This polemic would make no sense if the prophets admitted the real existence of several gods. Strict monotheism is already implicit in Mosaic preaching; what the Exile purifies is its formulation, not its substance.

Objection 5 — "All religions aim at the same Ultimate Real" (John Hick-style pluralism)

Strong formulation. The British philosopher John Hick (1922-2012), in An Interpretation of Religion (Yale University Press, 1989), maintains that all the great religions are culturally conditioned responses to the same "Ultimate Real" (the Real an sich). Yahweh, Allah, Vishnu, the Trinity, Brahman, the Tao, Buddhist Emptiness are so many personae and impersonae of one same mystery, never grasped in itself.

"The divine noumenon is a necessary postulate of the pluralistic religious life of humanity." — John Hick, An Interpretation of Religion, Yale University Press, 1989, p. 249^[61]

The Kantian noumenon/phenomenon distinction is central: of the Real we know only its manifestations, never the Real in itself. No religion therefore captures God in a privileged way; exclusivist Christianity would be ethnocentric.

Catholic answer. Radical religious pluralism is precisely the thesis targeted by the Dominus Iesus declaration of the Congregation for the Doctrine of the Faith (6 August 2000), signed by Cardinal Ratzinger and approved by John Paul II:

"The Church's missionary proclamation is today put at risk by relativistic theories, which seek to justify religious pluralism, not only de facto but also de iure (or as a matter of principle)." — Congregation for the Doctrine of the Faith, Dominus Iesus, § 4 (6 August 2000)^[62]

The central argument of Dominus Iesus is not that other religions are worthless — the Church recognizes their "seeds of the Word" and their dignity — but that the revelation of Jesus Christ is definitive, complete, and unique. No other tradition has access to the mystery of God in the same way as the one that knows that "the Word became flesh" (Jn 1:14).

On the philosophical plane, Hick's thesis is self-refuting. Hick affirms that no one can know the Real in itself, and yet he claims to know that all religions aim at the same Real in itself. How does he know this, if he is himself a prisoner of the cognitive condition he describes? His pluralist theory hoists itself above all religions while affirming that this vantage point is impossible. It contradicts itself in its very statement. The analytic philosopher Alvin Plantinga formulated this critique rigorously: to uphold Hickean pluralism, one must occupy a "from above" viewpoint that the thesis itself declares inaccessible^[63].

Above all, religions actually say incompatible things about God: the Christian Trinity is denied by Islam; the resurrection of the flesh is denied by Buddhism; the creator God ex nihilo is denied by Advaita Vedanta; Christ's divinity is denied by Judaism. These differences are not cultural nuances: they are logical contradictions. At least one of the positions must be false. The Catholic Church teaches, in fidelity to Revelation, that the Christian Trinitarian conception is true; but it honestly and explicitly recognizes the "rays of truth" present everywhere (Nostra Aetate § 2).

Objection 6 — "The contemporary cosmology of the multiverse suggests several causes"

Strong formulation. Contemporary theoretical physics seriously envisages the existence of a multiverse: chaotic inflation (Andrei Linde), string theory with its very numerous possible vacua, Tegmark's hypothesis of the mathematical multiverse. If nature itself ramifies into an infinity of universes, why not conceive a corresponding metaphysical plurality of first causes?

Catholic answer. The argument confuses two orders: the possible physical multiplicity of universes, and the metaphysical uniqueness of the first cause. Even if the multiverse exists, each universe remains contingent: it might not have existed, its laws might have been different, its inflation might never have started. A multiverse is only a multiplication of the contingent. But the contingent necessarily calls for a non-contingent cause, and this cause is unique by the classic Thomist ways.

William Lane Craig puts it pithily: "The multiverse hypothesis does nothing to eliminate the need for a creator and designer of the universe. […] A transcendent and personal creator and designer of the cosmos is needed whether the multiverse exists or not" ^[64]. Tegmark himself acknowledges that a multiverse-generating mechanism must possess its own laws and constants; one only pushes the question back one notch, not dissolve it.

The Thomist argument holds on the contrary a fortiori: the vaster, more complex, and more coherent the physical universe proves to be, the more acutely the question of its single foundation arises. The plurality of physical universes gives no reason to think there are several Gods; it rather underscores the depth of the single creative act.

Objection 7 — "The Christian Trinity is disguised polytheism"

Strong formulation. The objection is carried by both Judaism and Islam. Maimonides wrote that the Christian Trinity corrupts Israel's strict monotheism. The Qur'an is even more explicit:

"O People of the Book! Do not exaggerate in your religion […] and do not say: 'Three.' Stop! That is better for you. Allah is only one God." — Qur'an, sura 4 (an-Nisā'), verse 171^[65]

"They are certainly disbelievers who say: 'Indeed, Allah is the third of three.' Whereas there is no god but one God." — Qur'an, sura 5 (al-Mā'ida), verse 73^[66]

Islam ranks Christianity among the religions of shirk (associationism), that is, the guilty association of other beings with Allah's divinity. For Jews and Muslims, the Trinity necessarily seems to compromise uniqueness.

In its strongest form, the objection does not rest on an isolated verse alone: it rests on tawhid, the affirmation of God's absolute oneness, for which any plurality in God — persons, relations, distinctions — would compromise his unity. The Christian, who also confesses one God, must therefore show that the distinction of Persons does not divide the divine essence.

Catholic answer. The Trinity is not polytheism: it is precisely the opposite. It affirms one God in three Persons, not three gods.

The distinction is crucial. Three gods would suppose three divine substances, three numerically distinct divine natures. The Trinity affirms one single substance, una essentia, una substantia seu natura simplex omnino, as Lateran IV explicitly says^[67]. The three Persons are distinguished not by their essence, their perfections, or their being: they are distinguished only by relations of origin — paternity (the Father is begotten by no one), filiation (the Son is begotten of the Father), procession (the Spirit proceeds from the Father and the Son).

Saint Augustine formulated this in De Trinitate with definitive rigor: the divine Persons are not three substances, but three subsistent relations within the one divine substance^[68]. Saint Athanasius of Alexandria, already in the 4th century, defended the homoousia (consubstantiality) of the Father and the Son against Arianism, and extended the argument to the Holy Spirit in the Letters to Serapion (ca. 358-359)^[69]. The same position is confessed at every Mass in the Symbol of Nicaea-Constantinople, professed in 325 (Nicaea) and completed in 381 (Constantinople I)^[70]. The Athanasian Symbol settles it with a definitive formula:

"And yet not three gods, but one God. […] And yet not three Lords, but one Lord." — Quicumque Symbol (known as Athanasian), 6th c.^[71]

The council of Toledo XI (675) explicitly confesses "one God, not solitary, but in Trinity of Persons" ^[72], and the council of Florence (Decretum pro Iacobitis, 1442) repeats: "Father, Son, Holy Spirit: not three gods, but one God" ^[73].

On the metaphysical plane, the Thomist argument for uniqueness applies fully to the Trinity^[74]. There is only one divine essence, hence only one God; what distinguishes the Persons neither adds to nor subtracts from this essence, because subsistent relations are neither additional perfections nor privations — they are ways of being the one divine essence. The Trinity therefore does not contradict uniqueness: it reveals its inner depth, showing that divine being is eternally communion. The Catechism synthesizes this doctrine in paragraphs 253-256^[75], and the consubstantiality (homoousios) of the Son with the Father was fixed definitively already at the council of Nicaea I (325)^[76].

On one precise point, the objection misses the doctrine actually confessed: Qur'an 5:116 evokes a triad associating God, Jesus, and Mary — yet no Christian Church has ever taught that Mary is a divine person. On this point, the verse does not describe the Trinity as Nicaea, Constantinople, Toledo XI, and the Catechism confess it. The substantive objection drawn from tawhid remains, answered by all the foregoing: the Persons are neither three gods nor three parts of God, but three subsistent relations within a single essence — which neither divides nor multiplies divine being. For complete treatment, see The dogma of the Trinity and Islam.

Summary table of objections

One ultimate end, hence one coherent life

Divine uniqueness is not a quarrel for experts. It commands the inner coherence of human life. If God is one, then human life has one single ultimate end: to know him, love him, serve him, and share in his eternal beatitude. That is the whole meaning of the Catechism's first paragraphs:

"God, infinitely perfect and blessed in himself, in a plan of sheer goodness, has freely created man to make him share in his blessed life. For this reason, at every time and in every place, God draws close to man." — Catechism of the Catholic Church, § 1^[77]

Jesus summed up all spiritual wisdom in a single sentence:

"Seek first the Kingdom of God and his righteousness, and all these things shall be given to you besides." — Gospel according to Saint Matthew 6:33^[78]

If there were several competing gods, there would be no more absolute hierarchy of ends: one would have to serve one without harming another, negotiate compromises, choose allegiances, as in all ancient polytheist religions. Monotheism, by contrast, orders the whole moral life around a single focus. That is why the first of the Ten Commandments is: "You shall have no other god before my face" (Ex 20:3)^[79] — and the greatest commandment, according to Jesus himself: "You shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength" (Mk 12:30)^[80].

The freedom of the monotheist heart

Divine uniqueness also grounds a certain inner freedom. Ancient polytheism made man dependent on a network of local divinities, jealous, capricious, to be appeased by precise sacrifices and rituals under pain of reprisals. Monotheism frees man from this religious dispersion:

• there is only one Master to serve, who is at the same time Father;
• all other powers (idols, demons, stars, fortunes, States, ideologies) are relativized;
• the human conscience no longer has to divide itself among competing allegiances.

Saint Paul draws the practical consequence of divine uniqueness in a lapidary formula taken up by the whole Catholic tradition on the refusal of idolatry:

"You cannot partake of the table of the Lord and of the table of demons." — 1 Corinthians 10:21^[81]

The one Lord demands the one loyalty. Serving God and serving an idol — money, power, science alone, ideology — are ontologically incompatible, not only morally.

The trap of contemporary syncretism

One last remark is needed. In our societies, many think they honor all religions by saying that "all paths are equal" or "whatever name you give him, it is the same God." This is actually a lack of respect both for truth and for other traditions. None of the great religions recognizes itself in this equivalence: neither Catholic Christianity, nor Islam, nor Orthodox Judaism, nor Advaitin Hinduism, nor Buddhism — all affirm their own position as true.

The Catholic Church, since Vatican II, recognizes in other religions "rays of that Truth which enlightens all men" (Nostra Aetate § 2)^[82] — a luminous but precise formula. It does not say that all religions reach God in the same way. It says that the seeds of the Word are scattered everywhere, and that their fullness is in Christ^[83]. Respect for other traditions does not consist in denying the truth of Catholic dogma, but in recognizing in the other a share of the truth which we Catholics confess in fullness.

Credo in unum Deum: praying to the one God

Christian monotheism is therefore at once a metaphysical demand (an unlimited absolute cannot be several), a revealed datum (Israel's Shema confirmed and unfolded by Christ), and a condition of spiritual coherence for human life^[84]. There is only one God, because there can be only one — and because this one God, who is subsistent Being itself, is eternally Father, Son, and Holy Spirit. In the Church's great liturgical prayer, this confession rises every Sunday through the first word of the Creed: Credo in unum Deum — I believe in one God.

When the Catholic recites these three words, he does more than confess a philosophical truth: he orients himself entirely toward the One. He refuses modern false divinities and frees his heart by turning it toward the only one worthy of absolute adoration. This is what Saint Augustine summed up in the most famous sentence of Christian spirituality:

"You made us for yourself, O Lord, and our heart is restless until it rests in you." — Saint Augustine, Confessions, book I, ch. 1 (ca. 397-400)^[85]

Pascal, beyond the metaphysical demonstrations of the Summa Theologiae and Aristotle's rigor, sensed that the one God is not only the conclusion of a syllogism, but a living presence. In the Memorial found sewn into the lining of his coat after his death, he had written on 23 November 1654:

"Fire. God of Abraham, God of Isaac, God of Jacob, not of philosophers and scholars. Certainty. Certainty. Feeling. Joy. Peace. God of Jesus Christ." — Blaise Pascal, Memorial, 23 November 1654^[86]

Pascal does not repudiate rational proofs: he recalls that they do not give the living God, but prepare the heart to welcome him. Thomas and Aristotle make the one God intellectually necessary; believing experience makes him personally present. Both converge in the Creed: one God, one heart, one life turned toward him.

• The proofs of God's existence
• The cosmological argument
• The argument from contingency
• Cosmic fine-tuning
• The dogma of the Trinity
• Hinduism
• The Mormons
• Islam
• Buddhism
• Why reincarnation is a false belief
• Pascal's Wager
• The argument from consciousness
• The problem of atheism and zetetics

Main sources

• Saint Thomas Aquinas, Summa Theologiae, I, q. 3 (divine simplicity), q. 7 (infinity), q. 11, a. 3 (uniqueness). Leonine edition, vol. IV (1888). Eng. trans. Fathers of the English Dominican Province, Benziger Bros., 1947.
• Saint Thomas Aquinas, Summa contra Gentiles, book I, ch. 42 "That God Is One." Eng. trans. Anton Pegis, On the Truth of the Catholic Faith (1955); Joseph Rickaby, Of God and His Creatures (1905).
• Aristotle, Metaphysics, book XII (Lambda), 8, 1074a 31-1074b 14. Eng. trans. W. D. Ross; Tredennick (Loeb).
• Maimonides, Guide for the Perplexed, part II, ch. 1. Classic Eng. trans. M. Friedländer (1904); Shlomo Pines, University of Chicago Press, 1963.
• Fourth Lateran Council, constitution Firmiter credimus, 1215, DS 800.
• First Vatican Council, dogmatic constitution Dei Filius, 24 April 1870, ch. 1, DS 3001. Canons DS 3021-3025.
• Catechism of the Catholic Church, §§ 199-202, 253-256, 285.
• Second Vatican Council, declaration Nostra Aetate, 28 October 1965, § 2.
• Congregation for the Doctrine of the Faith, declaration Dominus Iesus, 6 August 2000.
• Congregation for the Doctrine of the Faith, Response on the validity of baptism conferred in The Church of Jesus Christ of Latter-day Saints, 5 June 2001.
• Saint Augustine, De natura boni (399), Confessions books III-V, Contra Faustum Manichaeum, De Trinitate.
• Edward Feser, Five Proofs of the Existence of God, San Francisco, Ignatius Press, 2017. ISBN 978-1-62164-133-9.
• Joseph Ratzinger (Benedict XVI), Introduction to Christianity, Ignatius Press (original title Einführung in das Christentum, 1968).